The present invention relates to a new and improved construction of a safety apparatus or delay arming device for a spinning projectile fuze.
Generally speaking, the safety apparatus for a spinning projectile fuze as contemplated by the invention is of the type comprising a ball-shaped or spherical rotor which can rotate out of a safety or unarmed position into an armed or live position. A closure body member and a support member are provided, between which there is rotatably mounted the rotor. A first ring-shaped groove is provided in the closure body member or closure body. This first ring-shaped groove is located in a plane which is disposed essentially perpendicular to the lengthwise axis of the projectile. A second ring-shaped groove is provided in the ball-shaped or spherical rotor. This second ring-shaped groove, in the safety or unarmed position of the rotor, is located in a plane which is disposed substantially perpendicular to the projectile axis. Also, there is provided a safety spring in the form of a substantially ring-shaped disk or plate member which protrudes both into the first groove and also into the second groove and serves to secure the rotor in its safety position. This safety spring can be deformed by the firing acceleration and by the spin, for the purpose of freeing the rotor so that it can move into its armed or armed position.
A state-of-the-art time-delay fuze of this general type has been disclosed in U.S. Pat. No. 3,595,169, granted July 27, 1971. Such time-delay fuze contains a ball-shaped rotor which is rotatably mounted in a hollow cavity or space of the fuze housing. The firing pin, this hollow cavity and a booster charge are located along the longitudinal axis of the fuze. The rotor contains a detonator cap within a continuous bore of the rotor, and a disk-shaped ring, which protrudes into a groove of the rotor, retains the rotor along with the detonator cap in a safety position. To release the rotor for movement into its armed position the disk-shaped ring must be pressed flat by the firing acceleration and enlarged by the spin.
However, this prior art safety ring does not ensure for any adequate safety during transport of the projectile. If vibrations occur during the transport of projectiles equipped with such fuzes, then it can happen that the rotor will rotate into its armed position.
A further known safety apparatus for spinning projectiles of the aforementioned type is disclosed in German Patent Publication No. 2,539,750, published Oct. 11, 1979. Such safety apparatus contains a horseshoe-shaped safety element which is already deformed by the projectile spin to such an extent that the rotor can rotate into its armed position. Such safety element does not comply with the security requirements which are frequently placed upon such type of safety apparatuses.
Other prior art constructions of delay arming devices or the like have been disclosed, for instance, in U.S. Pat. No. 2,682,835, granted July 6, 1954, British Pat. No. 107,246, published June 25, 1917, Belgium Pat. No. 539,630, granted Jan. 7, 1956, and French Pat. No. 2,034,677, published Nov. 11, 1970.